docs: def addGraphic(self, layerName, geometry, symbol):
          """ loads a geometry (ArcPy Geometry Object) into Graphic Layer"""
          allowed_geomtypes = ['polygon', 'polyline', 'point', 'multipoint']
          if not (geometry.type.lower() in allowed_geomtypes):
              return False, layerName
          geom = _unicode_convert(json.loads(geometry.JSON))
          geomType = self.__look_up_geom(geometry.type.lower())
          if layerName in self._storedFeatures:
              self._storedFeatures[layerName]['featureSet']['features'].append({"geometry":geom,
                                                                                 "symbol":symbol.asDictionary})
          else:
              template_ld = {
                  "layerDefinition":{
                      "name":layerName,
                      "geometryType":geomType
                      },
                  "featureSet":{
                      "geometryType":geomType,
                      "features":[{"geometry":geom,
                                   "symbol":symbol.asDictionary}]
                  }
              }
              self._storedFeatures[layerName] = template_ld
          return True, layerName